Typically, crystalline propylene polymer materials, such as polypropylene and propylene polymer based copolymers have found extensive use in various formed articles, such as injection-molded articles, blow-molded articles, films, sheets and fibers, because of their excellent mechanical properties. However, due to their nature, crystalline propylene polymer materials are to varying degrees unstable in regards, for example, to oxidation and to ultraviolet radiation. In addition to the above disadvantages, they are also poor in transparency. To improve the transparency of polyolefins, nucleating or clarifying agents are generally incorporated therein as described in U.S. Pat. No. 4,388,119 which discloses a composition consisting essentially of a solid powdery dibenzylidene sorbitol coated with a higher fatty acid.
U.S. Pat. Nos. 3,640,928 and 3,840,494 and Canadian patent 997,353 disclose synthetic polymer compositions stabilized against photo- and thermo-deterioration by adding a sufficient amount of a piperidine derivative.
Lower processing temperatures are preferred in the industry to prevent the degradation or decomposition of the propylene polymer material. However, at lower processing temperatures white specks of unmelted and poorly dispersed stabilizers and/or nucleators are found in the molded articles because the processing temperatures are lower than the melting points of the particular stabilizer and/or nucleator being used. Thus, there is a desire to find a way to use certain stabilizers and nucleators at lower processing temperatures, without obtaining white specks in the final product.